1. Field of the Invention
Aspects and embodiments relate to: a plasmonic switching device and a method of providing a plasmonic switching device; an electromagnetic waveguide transmission modulation device and method of providing such a device; and a further electromagnetic waveguide transmission modulation device and method of providing such a device.
2. Background
Photonic circuits can be equipped with photonic components which have a greater speed and can handle larger bandwidths when compared to equivalent electronic components. However, such photonic components may be prevented from attaining particularly compact, for example, nanoscale, dimensions as a result of diffraction.
One approach to overcome the diffraction limit recognises that utilisation of surface plasmon polaritons (SPPs) can be useful. Such SPPs arise due to the coupling of light to free electron oscillations at an interface between a dielectric and a metal. The ability to control and manipulate light on the nanoscale via SPP modes can offer a means to construct compact optical components for use in applications including: data storage, information technologies and sensing. In order for plasmonic circuitry to be realized, a component which is able to efficiently operate to “switch” a signal is required. It is recognised that switching may occur by means of alteration of propagation characteristics or alteration of excitation of SPPs.
Plasmonic systems may be implemented to demonstrate active functionalities. Such plasmonic systems may incorporate, for example, thermo- and electro-optic media, quantum dots, and/or photochromic molecules and such systems are achieving incremental performance progress in relation to switching and modulation applications. However, long switching times (>nanosecond) and/or the need for relatively strong control energy (˜μJ/cm2) to observe sensible signal modulation (35% to 80%) can limit the practical use of such structures in signal processing or other active opto-electronic nanodevices. It will be appreciated that in order for active plasmonics to offer a viable technological platform, both the magnitude and speed of an employed nonlinearity, together with the spectral/spatial tunability of that effect must be improved.
It is desired to provide an improved plasmonic device.
Optical components play a key role in industry today and can frequently be found in common instrumentation devices. Such devices are used to serve a broad range of applications, in areas as varied as: communications systems, health and safety, security systems, and biometrics. Optical components provide a means to implement some key functionalities and can allow the harvest, generation, conversion, processing and other manipulation of optical signals. There is constant demand for optical devices to allow or support higher integration, portability, speed, and bandwidth, whilst performing with reduced power consumption.
It is desired to provide an improved optical signal manipulation device.